Brake-pipe vent valve for automatic train-stop apparatus



Noir. 9, 1926.

S. G. NEAL BRAKE PIPE VENT VALVE FOR AUTOMATIC TRAIN STOP APPARATUS Filed Jan. 23. 1925 2 Sheets-Sheet 1 ATroRNEYS v Nov. 9 1926. Y 1,606Q31'8v f s. G. NEAL j BRAKE PIPE VENT VALVE FOR AUTOMATIGTRAIN s'roP APPARATUS Filed Jan, 23f 1925 2 Sheets-Sheet z t v '0. U

D y) 5k w g2 S- E* RM k Main .Raser-V01' INVENTOR Spencer //eaL A@wfg lso Patented Nov. 9, 1926.

ET 'r SPENCER Gr. OF N1?V WYORK, N; Y., ASSIGNOR TO AU'ICOlIIATICl STRAIGHT AIR BRAKE COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

BRAKE-PIPE VENT VALVE non AUTOMATIC TRAIN-STOP APPARATUS.

Application 4flecllanuary 23, A1925. SerialNo. 4,259.

In electrically operated train stopping apparatus it is necessary to provide on the train an automatically operating valve to make the desired service reduction in brake pipe pressure to apply the brakesrwhen the train stopping apparatus is effective. Such a valve is desirably adjustable manuallyv in order that it will make any desired reduction in brake pipe pressure, It is also desirable that such Valve shall so operate asto deprive the engineer or" the power to increase the brake pipe pressure immediately following the automatic application ot the brakes through the operation of the train Stop Vor train control apparatus.

One of the principal objects of this inven= tion is to provide an automatically operating brake pipe vent valve which will' make a certainpredetermined service reduction in brake pipe pressure when the train control apparatus is effective.

Another importan-t object of the invention is to provide an automatically operating valve which will makethe desired service reduction inbrake pipe pressure and at lthe same time cut off communication between the main reservoir and the engineersvalve so that the engineer will be deprived of the power of increasingthe brake pipe presssure through the usual manipulation of the en-A gineers valve, immediately following an operation of the train control apparatus, but leaving it within the power of the engineer to `make further reductions of brake pipe pressure by thefusual manipulation of the engineers brake valve for that purpose.

Another important object of the invention is to provide such` anrautomatic vvalve with means to hold it normally inoperative so that the engineersbrake valve may be manipulated in the usual manner for the control of the train by theair brakes.

Another important object of the invention is to provide means whereby the automatically operable valve may be manually adjusted to make any desired service reduction in brake pipe pressure, within reasonable limits.

f Another important object of the invention is to provide an automatic valve, as described herein, adapted to operate in any desired degree of brake pipe pressure so that the valve may be used, without special adjustment, in passenger service with a high brake pipe pressure and also in freight serv-v icewhere a comparatively low brake pipe pressure is used.

' YAnotherA object of the invention is to provide an automatic valve, as described herein,l of such construction that the high main reservoir pressure will move it to operative position against merely atmospheric pressure. This insures theV lvalve moving to operative position instantly and positively.

In the drawings:

Fig. l is a vertical longitudinal sectional view of the automatic train stop valve showing theapparatus in normal or ineffective position;

Fig. 2 a, view similar to Fig. l showing the parts in operative position; and i Fig 3 a vdiagrammatic view showing the automatic train stop valve, the main reservoir and the engineers brake valve.

Referring to the various parts by reference characters, A designates the main reser-r voir, B the engineers brake valve, C the brake pipe vent valve and D the brake pipe. The brake pipe is connected to the vent valve atl. The main reservoir is directly connected to the vent valve by pipe 2 and the engineers brake valve is connected to the vent-valve by pipe 3.. Brake pipe passage lpis in direct communication with a chamber 4 through a passa-ge la. The upper wall of chamber fl is Vformed by a movable abutmentror diaphragm 5. A diaphragm 5a isarranged above the diaphragm 5 and parallel therewith to form a mainl reservoir chamber 4a between said diaphragms. The diaphragms 5 and 5 are of the same area. Above diaphragm 5a, and spaced a suitable distance therefromis a large diaphragm 6, this latter diaphragm being arranged ina large chamber 6a. The space between the diaphragms 5a and 6 is open to atmosphere directly through a port 6 so that there will be no pressure between said diaphragms. Above the diaphragm 6 is formed a control chamber 7 and'infopen communication with said chamber is a reduction control reservoir or chamber 7a, saidxreservoirbeing in open communication with chamber v7 through `port 71% The purpose of this reservoir is to augment the volume ofy chamber 7 so that there will be no appreciable reduction in chamber 7 when the Avalve is in `operative y position, as hereinafter described. The three diaphragme are .rigidly connected together by means of a jointed central stem 8 formed with a central longitudinally extending pas'n sage 8PL which opens at its lower end into the main reservoir chamber 4a and opens at its upper' end into a small chamber 8b formed in the stem above the diaphragm 6. The stem 8 above the chamber 8 is tubular and .in said tubular portion is arranged a valve stem carrying a valve 9 at its lower end and a valve 9 at its upper end. A portion of the stem is reduced in diameter, or provided with longitudinal grooves to form an air passage alongsaid stem. The valve 9 seats on the upper wall of the chamber 8b, a spring 9etending normally tol press the valve 9 upwardly to its seat. The tubular upper portion of the stem 8 is formed with lateral ports 8c which place the control chamber 7 in con'imunication with the interior of the tubular stem adjacent the reduced portion of the stem carrying the valve 9. The valve 9 controls a port ,which connects the chamber 7 with a passage 11. The vdiaphragms are held in their normal position by means of a spring 10 arranged in the chamber 4 and'bearing at its upper end on the lower end of the stem 8 and at its lower end in a vertically adjustable cup 10u. By manually adjusting the threaded cup 10L the pressure 'exerted by the spring 10 on the diaphragm structure may be increased or diminished as desired, within reasonable limits. The adjustable cup 10a islocked in its adjusted position by means of a protecting cap 1()b which is adapted to be screwedl on the adjustable cup and locked against the outer side of the valve casing. There is a slight -play or lost motion between the upper end of the stem 8 and the under side of the valve 9a. This permits the diaphragm 6 and the tubular stem 8 toi-isc slightly after the valve 9a is seated and ``or the purpose ot' moving the seat away from the valve 9. This movement of the diaphragm and the tubular stem 8 places the chamber 4a in communication with the chamber 7 and closes communication between the chamber 7 and the passage 11. When the diaphragm structure and the tubular stem 8 carried thereby move downwardly valve 9 will be seated to close communication between chamber 4% and chamber 7 and valve 9a will remain closed. Brake pipe pressure will be registeredy in chamber 4 under the diaphragm 5. The diaphragm 6 is of greater area than diaphragm so that a lighteror a le^s degreeoi, pressure in chamber 7 will overcome a higher brake pipe pressure in chember 4.

In the valve casing is formed a slide valve chamber 12in which 1s arranged a slide valve 12El operating on a valve seat. The

slide valve is connected to a longitudinally extending valve stem 13, said stem being connected at one end to a main piston 33 operating in a chamber 32. The slide'valve 12a is held in its inner, normal, inoperative position by spring 50, suitably arranged in the valve casing. The valve 122" is formed with a vport l5 which, in the normal inoperative position ot the valve, connects the valve chamber 12 with a chamber 17 above a piston 18,. Below the piston 18 is a chamber 19 which is connected by passage 2() with the main reservoir connection 2. Passage 2O is connected by a passage 14 direct to the valve chamber 12 so that main reservoir pressure will always be present in the said chamber. A depending' central stem 18:L is connected to the piston 18 and carries at its lower end an upwardly seating valve 21. rlhe valve 21 is arranged in a chamber 21a which is in direct vcommunication with the 'engineers brake valve connection 3.k The valve 21 in the upper position of the piston 18, closes communication between chamber 19 and 21 and thereby closes communication between the main reservoir and the engineers brake valve. l/Vhen this valve 21 is closed the engineers brake valve cannot be vmanipulated to place the main reservoir in communication with the brake, pipe. The engineer may, however, place the engineers brake valve in application position or in emergency position and therebymalre a turther reduction in brake pipe pressure for the purpose of increasing the pressure in the brake cylinders. He cannot, however, release the brakes until the apparatus has been restored to normal position and the valve 21 has been movedV to open communication between chambers 19 and 21u.

is arranged as a movable abutment separating chambers 22 and 27, chamber 22 being above the piston and 27 below it. The piston 23 carries a depending central stem whose lower end forms an equalizing discharge valve 43 adapted to close an exhaust port 44. Normally the valve is seated and the port closed merely by the weight of the piston and the valve. The chamber V22 is connected to a port in the slide valve seat by a passage 24.V The chamber 27 is connected to a port in the slide valve seat by a passage 28. The slide valve is formed with a cavity 29 which in the normal iiioperative position of the'slide valve connects port and passage 28 with al port 30 which leads to atmospheric port A1 so that in the normal iii-operative position of the slide valve there will be no pressure in chamber 27 and valve 43 will be seated. The slide valve is also formed with a cavity 25, which, in the normal in-operative position of said valve, will connect the port and passage 24 to a port 26 which leads to atmospheric port A2,'

so that in the said position of the slide valve, chamber 22 will be open to atmosphere and there will be no pressure therein. Passage the slide valve seat.

11 leads to a port 11*l in the slide valve seat adjacent the port 26 and in the normal inoperative position of the main slide valve, cavity connects said Aport 11L to the port 26.

The brake pipe connection, or passage 1 is connected by a passage`37 lto a port37a in The main reservoir chamber s is connected by a passage 38 to a port 33a leading into the slide valve chamber 12 so that main'reservoir pressure will always be present in chamber 4a. The chamber 7 is connected by a passage 39 to a port in the slide valve seat. The slide valve is provided with a cavity 41 which, in the operating position of the slide valve,

'will connect the passage 16 to a port 42 which leads to atmospheric port A3. The main piston 33 is provided with a small leak port 33al which connects the slide valvev chamber 12 to the chamber 32.

The chamber 32 is connected by a passage 35 to an exhaust passage 36. The connec* tion between these two passages is controlled by a downwardly seating electrically operated exhaust valve 31. The valve 31 is formed with a depending stem 31 which carries at its lower end a head 31". Below the said head and normally pressing the valve 31 upwardly away from'its seat is a spring 31C. The upper end of the valve 31 is provided with a core which is adapted to reciprocate in an electric coil 31d, shown in dotted lines. lVhen the coil is energized by current flowing therethrough the core carrying the valve 31 is drawn downwardly and the valve 31 is held to its seat. The downward pull of the solenoid coil is suiiicient to seat the valve 31 against the pressure of the spring 31c and against thev air pressure in chamber 32. When the current through the coil is broken and the coil cle-energizes the spring and the pressure in chamber 32 will move the valve upwardly away from its seat and open the chamber 32 directly to the exhaust passage 36. The piston 33 is provided with lugs which are adapted to engage the end wall of the chamber 32 to prevent the piston from sealing the exhaust passage 35. The electric circuit through the coil 31d is brokenby the automatictrain stop apparatus when conditions require that the train brakes be applied.

0 pemton.

lVhen the brake system is being charged the engineers brake valve is operated tofull release or running position in the usual manner and air direct from the mainreser-y voir will flow to chamber 19 below piston 18 and will also ylow into chamber 12 through passage 14. Air will also flow from chamber 12 through passages 15 and 16 to chamber 17 above the piston 18. The pressure being balanced on opposite 'sides of the piston 1S, the piston and the valve 21 will be forced to their lower position by the pressure on the valve 21 and said valve will.

remain open. Main reservoir air williiow from chamber 21a through. the connection 3 to the engineers brake valve and thencev to the brake pipe in the usual manner..` The circuit through `the coil 31d is normally closed, thereby holding valve 31rseated to close the exhaust passage 35. lVith thev valve `31 closed, air will leak through the port 33 and there will be an equalization of pressures on opposite sides of the piston. 33 and the spring 50 willl thereupon hold the slide valve in its inner inoperative position. Main reservoir air will also flow from chamber 12 through passage 38into chamber 4a. Brake pipe air will flow through pipe D to connectionV 1 and thence lthrough port 1LL into chamber 4L. The spring 10 inv chamber 4 will normally hold thediaphragm structure and the stem 8 in ltheir upper positions. This willseat valve 9a and unseat valve -9. Air from chamber la will flow upwardly through the passage 8a past valve 9 through ports 8c into chamber 7. vThediaphragms 5 and 5d being of equal area the pressure in chamber il will be balanced and therefore will have no eii'ect upon the diaphragm structure and will not end to move it in either direction. Chamber 6u is open to atmosphere. The pressure in chamber 7 will buildup until it exerts a downward force sufficient to overcome the upward force of the pressure in pressure in chamber 7y has been increased.

to within twenty-five pounds of the existing brake pipe pressure in chamber 4. Should the spring 10 Vbe compressedand adjusted to exert an upward pressure on the diaphragm 5 to assist the brake pipe pressure in chamber 4L in opposing the downward force exert-` ed by pressure in chamber 7 it would be necessary to develop al higher pressure in chamber 7 to overcome this increased resistance. By manually adjusting the spring 10 to vary its pressure on diaphragm 5 the degree of pressure necessary to be built up in chamber 7 may be varied. By providing for different adjustments of the spring tensions the diiference in pressure between chambers 4; and 7 is optional between equalization and a twenty-five pound .dierential This diferential in pressure controls the amount of service brake pipe reduction when lthe brake pipe vent valve is brought into operation.

afik

Valve 9L is provided for the purpose of preventing an excess pressure in chamber 7. Should the pressure build up in chamber 7 through a leakage past valve 9, the perfect balance between the pressures in chambers 7 and 4 willV be destroyed and the diaphragm and the parts directly connected therewith will be lowered, thus opening valve 9a to permit the escape of air from chamber 7 at the same rate as the leakage past valve 9. Air flowing past valve 9a will flow direct to atmosphere through passage 11, cavity 25 and atmospheric port A2.

vWhen, in the operation of the automatic train stop apparatus, or otherwise, the coil 31d is cle-energized, the spring 31 and the pressure in chamber 82 rwill immediately lift valve 31 and thereby open chamber 82 direct to atmosphere. The main reservoir pressure in chamber 12 will instantly and positively forcethe piston 33 and the Aslide valve connected thereto outwardly against the pressure of spring 50 and willhold the slide valve in operative position (see Fig. 2).

r This position of the slide valve willcut off communication betweenthe main reservoir and chamber 17 above the piston 18, and cavity 4,1 will connect passage 16 to atmospheric port A3, thereby venting chamber 17 to atmosphere. The high main` reservoir pressure in chamber 19 will then instantly and positively seat valve 21 and cut off communication between the main reservoir and the engineers brake valve. This will prevent the engineer from so manipulating his brake valve as to increase brake pipe pressure for a release of the brakes. The brake valve may be manipulated to reduce brake pipe pressure either by a movement to service position or by a movement to emergency position.

In the operative position of the slide valve, cavity 29 places port and passage 37-37ain communication with passage 28 and brake pipe air will flow to chamber 27 below the equalizing discharge piston 25.v This pres-V sure in chamber 27 will raise the piston 23 and open valve 43 to permit brake pipe pressure to discharge to atmosphere. The cavity 25 of the slide valve will connect passage 39 and port Ll() to passage 24 so that the air from chamber 7 may flow direct to chamber 22 above the equalizing discharge pist-on 23. As herein described pressurevin the control Ychamber 7 is maintained at a predetermined pressure below the brake pipe pressure. Thus the differential in pressure between the controh chamber pressure in chamber 22 andthe brake pipe pressurev in chamber' 27 will be the same as that between that in chamber l and the control chamber .7. VVit-h this differential in pressure existing on opposite sides of the piston 22 the brake pipe pressure will raise vthis piston to open the equalizing discharge vvalve 13 and brake pipe pressure will be vented direct to atmosphere at a service rate through passage 37 and the connectedfports and pas sages leading to the exhaust port 14. The brake pipe pressure will continue to flowto atmosphere until the pressure in chamber 27 has been reduced to an equality with the pressure in chamber 22, at which time the valve will close. As hereinbefore pointed out, by varying the tension of the spring 19 the amount of brake pipe reduction secured through the operation of the apparatus may be varied at will. To prevent the escape of air from chamber 7 to atmosphere, should valve 9L be open when the apparatus becomes operative, the passage 11 is cut. offfrom the atmospheric port A2 and closed when the.

slide valve is in operative position as shown in Fig. 2.

The amount of brake pipereduction secured through the operation of the vent valve is governed entirely by the differential in pressure between the brake pipe pressure in chamber l and the pressure in the control chamber 7.

W'hen the coil 31 is again energized the valve 31 will be closed. Air will leal'. through port 33, and, when, the pressure in chamber 32 has been raised sufficiently, thespring 50 will move Vthe slide valve lto its inner inoperative position as shown in Fig. 1. Main reservoir air will then flow direct to chamber 17 and equalize with the pressure in chamber 19, thereby permitting the pressure in said chamber to force the valve 21 to open position. The chamber 22 will be vented to atmosphere through cavity 25 and atmospheric port A2 and the equalizing discharge valve will.A close. The differentialA of pressure again rwill be established in chambers land 7.

The diaphragms 5 and 6 are so proportioned as to give a predetermined ratio of pressures between the chambers 4 and 7. This ratio of differential pressures will be maintained regardless of the degree of brake pipe pressure in chamber 4. This pressure may be seventy pounds for brake service, or one hundred ten for passenger service. These diaphragms are preferablyl so `proportioned that when the vent valve is used in freightservice or inV passenger service it will bring aboutV approximately the standard brake pipe reduction for both of the said services. The brake pipe reduction brought about by the operation of thevent valve will be higher in passenger service than in freight service due to the fact thata higher brake pipe pressure is used in passenger service. The ratio of this reduction, however, remains the same in all cases.

What Tclaim is:

1. A brake pipe vent valve for automatic train stop apparatus comprising a valve casing formed with a brake-pipe chamber and a means for opening said valve when the elec-` 1. trically operatedmeans is rendered inefecy.

tive,`and meansoperatedfby the opening of the said exhaust valve to connect the control chamber to a chamber on one side of the equalizing discharge piston and to connect the brake pipe to a chamber on the other' side of the equalizing discharge piston, the brake pipe VpressureopposingV the cntrol chamber pressureandopening the equalizing discharge valve to permit brake pipe )ressure to exhaust toV atmosphere until'said rake pipe pressure has eq'ualized with, the pressure inthe control c liaiifibe'r,

2. A brake pipe vent valveIv for. autoP matic .train stop` apparatus comprising a valve casing Vformed with' a brakey pipe chamber and a control chamber, vmeansfo'r establishingr apressure in 'thecontrol ber ata predetermined degree of pr ber, an equa'liz'ing `dis`clia1ge valve, Aair equal'-I izing discharge piston connected tosaid valve, an exhaust valve, electrically operated' means for controlling the operation ofthe exhaust valve, and means operatedby thev opening of the said exhaust valve to' `c0'riy nect the control chamber'to a chamber on one side of the lequalizint'q discharge piston and to connect the brake'pipe. to av chamber on the other side of' the 'equaliz ing discharge piston vthe br'alie pipe pres; sure opposing' the control chamber pres; sure and' opening the equalizinghdischarge valve to permit brakey pipe pressure yto exhaust to asmosphere until said brakefpipe pressure has equalized `With thepre'ssure iny the control chamber.

3. A brake pipe `vent valve forl automatic' train stopiapparat'us compris-ing a 'valve casing formed' with a brake'V p1 a control chamber, means for establishing' a pressure in the control chamberfat a predetermined degree of 'pressure below' the:`

pressure in :the vbrake pipe'chamber, an equal-v izing discharge valve,A an jequ'ali'zingv di s{ charge piston-connected to said valve, an exhaust valve, electrically.` operated means for controlling the operation Yo't the exhaust'l valve, and means operated by the opening of the said exhaust valve to cofnnect the'control chamber to a chamber on one sid-e of the equalizing'discharge piston and-to connect the brakefpipejtov a chamber on the other side ofthe equaliziiig discharge piston, thebralre pipe pressure opposing the; con# trol chamber pressure and. opening thebe chafniber lniet 4. 'A brakepipe vent valve torautomatc train stop apparatus comprising a valve cas-` ing formed with a brake pipe chamber and a `control chamber, means -operated `by the pressures in the said' brake pipe chamber and inY the control chamber Jfory establishing `a pressure yin the control .chamber at a predetermined degree of pressure below the pressure in the brake pipe chamber, an equalizing discharge valve, an vequalizing discharge' piston connected to said valve, an exhaust valve, electrically Voperated means for hol-dingthe exhaustvalve closed', means for opening said lvalve when the electrically operated means is render-edy ineffective, and meansioperated by the opening of the said exhaust valve toy connect the control chamber to a chamber on one side oi' the equalizbrake pipe to a chamber on the other side of the equalizing dischargefpiston, the brakeV pipepressure-opposing the control chamber pressure and opening the fequalizing ,dief 4 charge valve to permit brakepipe pressure ure below the pressure inthe Ybrake ,pipe cliarn/ a to exhaust 'to atmosphere until said brake sure in the control chamber...

5. brake pipe ventlvalve for-automatic trainr stop apparatus comprising a valve cas-v ing formed With a brake pipe chamber and a control chamber, means. for establishing a pipe pressure has' equalized with thek pres-` pressure inthe control chamber at a predetermined degree of pressure'below the pres-v sure in `the brake pipe chamber, an equaliz-v ing discharge valve, lan exhaust valve, electrically operated means forcontrolling the operation ofthe exhaust valve, and means automatically operating` uponr the opening of thesaid exhaust valve to open thewe'qual-v izing discharge valve, the brakegpipe presa. pressure'in thec'ontrol chamber at; a'4 predeterminedy .degree of pressurevbelotv the pressure in the brakev pipe chamber," .an equalizing, discharge valve, an l exhaust valve, electric'all'7 operated` means forcontrolling the operation of the exhaust valve, and means lautomatically operatinggupon-,the openin'g'ofthe said exhaust valvetdofpen Vthe* equalizingA discharge valve, Y the brake pipepressjure oppsing the central chamber vsure opposing the control chamber pressure pressure to hold the equalizing discharge valve open to permit brake pipe pressure to exhaust to atmosphere until said brake pipe pressure has equalized with the pressure in the control chamber. I

. 7 A brake pipe vent Valve for automatic train stop apparatus comprising a valve casing formed with a brakepipe chamber and a control chamber, means for establishing ay pressure in the control chamber at a pre-V determined degree of pressure below the pressure in the brake pipe chamber, an equalizing discharge Valve, an exhaust valve, elec trically operated means for controlling the operation of the exhaust Valve, and means automatically operating upon the opening of the said exhaust valve to open the equalizing discharge valve, the brake pipe pressure opposing the control chamber pressure to hold the e ualizinfr dischar e valve o en to erfl e mit brake pipe pressure to exhaust to atmos-f phere from the chamber. l

V8. A brake pipe vent Valve for automatic equalizing discharge Valve train stop apparatus comprising a valve casing formed with a brake pipe chamber and a control chamber,l means operated by the pressures inthe said brake pipe chamber and in the control chamber for establishing a pressure in the control chamber at a predetermined degr-ee ofV pressure below the pressure in the brake pipe chamber, an equal-l izing discharge Valve, an exhaust Valve, electrically operated means for controlling the operation of the exhaust valve, and means automatically operating upon the ope-ning of the said exhaust valve to open the equal-V izing discharge valve, the brake pipe presf sure opposing the control chamber pressure exhaust Valve, means for controlling the op-V eration of the exhaust Valve, and means automatically operating upon the opening of' the said exhaust valve to open the equaliz'ing discharge Valve, the brake pipe pressure op-k posing the control chamber pressure to hold the equalizing discharge valve open to permit brake pipe pressure to exhaust to atmosphere until said brake pipe pressure has equalized with the pressure in the control chamber. 'Y

l0. A brake pipe vent Valve for automatic train stop apparatus comprising a brake pipe chamber and a control chamber. meanspoperated by the pressures in the said brake pipe chamber and in the control chamber for establishing a pressure in the control'chame ber at a predetermined degree of pressure below the pressure in the brake pipe chamber, an equalizing dischargeyalve, an exhaust valve, means for controlling the operation Vof the exhaust valve, and means automatically operating upon the opening of the said exhaust Valve to open the equalizing discharge valve, the brake pipe pressure opposing the control chamber pressure to hold the equalizing discharge Valve open to permit brake pipe pressure to exhaust to atmosphere until said brake pipe pressure has equalized with the pressure inthe control chamber.

yll. A brake pipe vent Valve comprising a brake pipe chamber and a control chamber,

means for establishing a pressure in the con-` trol chamber at a predetermined degree of pressure below the pressure in the brake pipe chambenan equalizing discharge valve, an exhaust Valve, means for controlling the operation of the exhaust valve, and means automatically operating upon the opening oif the said exhaust Valve'to open the equalizing discharge valve, the brake pipe pressure opposing the control chamber pressure to holdV the equalizing discharge valve open to per mit brake, pipe pressure to exhaust to' atmosphere from vthe equalizing discharge valve chamber. c f f l2. A brakelpipe Vent` said brake pipel chamber and in the control chamber for establishing la pressure-in the control chamber at a predetermined degree of pressure below the pressure in the brake pipe chamber, an equalizing discharge `Valve, an exhaust Valve, means or'conti'olling the operation of the exhaust'valve, and means` for automatically operating upon the opening or" the said exhaust valve to open the equalizing discharge valve, the brake pipe pressure opposing the control chamber pressure to hold the equalizing discharge valve open to permit brakeV pipe pressure to exhaust to atmosphere from the equalizing dis-` charge Valve chamber. Y A

Y 13. A brake* pipe yent valve for automatic trainstopjapparatus comprising a brake pipe chamber and a control chamber, means for establishing a pressure in the ycontrol chamber at a predetermined degree of presvalye' coniprisin a brake pipe chamber and a control chamber, means operated by the pressures in rthe ien permit brakey pipe pressure to exhaust to atmosphere until said brake pipe pressure has equalized with Vthe pressurev in thecontrol chamber. 1

14. A brake pipe vent valve for automatic train stop apparatus comprising a brake pipe chamber and a control chamber, means operated by the pressures in the said brake pipe chamber and in the control chamber for establishing a' pressure in the control chamber at a predetermined degree or pressure below the pressure in the brake pipe chamber, manually operable means to vary the degree of pressure established in the control chamber, an equalizing discharge valve, an

exhaust valve, means for controlling the operation of the exhaust valve, and means automatically operating upon the opening of the said exhaust valve to open the equalizing discharge valve, the brake pipe pressure opposing'the control chamber pressure to hold the equalizing` discharge valve open to permit' brake pipe pressure to exhaust to atmosphere until said brake pipe pressure has equalized with the pressure in the control chamber` 15. A brake pipe vent valve comprising a brake pipe chamber and a control chamber, means for establishing a pressure in the eon trol chamber at ya -predetermined degree of Y pressure below the pressure in the brake pipe chamber7 manually operable means to vary the degree of pressure established in the control chamber7 an equalizing discharge valve, an exhaust valve, means Jfor controlling the operation of the exhaust valve, and. means automatically operating' upon the opening of said exhaust valve to open the equalizing discharge valve, the brake pipe pressure opposing the control chamber pressure to hold the equalizing discharge valve open to Apermit brake pipe pressure to exhaust to atmosphere from the equalizing discharge valve chamber. r

16. A brake pipe vent valve comprising a brake pipe chamber and a control chamber, means operated by the pressures in the said brake pipe chamber and in the control charnber for establishing a pressure in the control chamber at a predetermined degree of pressure below` the pressure in the brake pipe chamber, manually operable means to vary the degree of pressure established in the control chamber7 anequalizing discharge valve, an exhaust valve, means for controlling the operation of the exhaust valve, and means automatically operating upon the opening of the said exhaust valve to open the equalizing v discharge valve, the brake pipe pressure opposing the control chamber pressurev to hold the equalizing discharge valve open tolpermit brake pipe pressure to exhaust tofatinosphere from the equalizing discharge valve chamber. y j

f 1T; A brake pipe vent valvefo'r automatic train stop apparatus comprising a4 brake pipe chamber, a control chamber, a movable abutment subject to the lpressure in the brake pipe chamber, a movable abutment subject to the pressure in the control cham'- ber, this latter abutment lbeing larger in area than the trainv pipe pressure abutment7 means rigidly connecting said two abutments whereby `the pressures in said chambers Will oppose `each other, a valve adapted to be openedv and closed by the movements of the abutments and when open to admit airinto the control chamber, valve adapted to be operated by the niovements of the abutments and when open to Aexhaust air from the control chamber, a

spring bearing on the brake pipe pressure abutment and adapted-to opposethe force exerted by the pressure in the control chamber, means for manually adjusting the tension of said spring, an equalizing discharge valve, an exhaust valve, -means for control- Vling the operation of the exhaust valve, and

means automatically operating uponl the opening-of the saiid exhaust valveto open the equalizing discharge valve, the brake pipe pressure opposing the control chamber pressure to hold the equali'zing discharge valve `to the pressure in the control'chamber this latter' abutment being larger in area'than the train pipe Lpressure abutment, means rigidly connecting said Vtivo abutments whereby the pressures in said chambersivill oppose each other, a valve adapted'to be opened and clos-ed by the movements .of the abutments )and When open toA admit 'air into the control chamber, al valve adapted lto be operated by the movements of the abutments and when open to exhaust air from the control chamber, a springl bearii'ig on the brake pipe pressure abutmentand. adapted to op,- pose the force exerted by `the pressure in the control chamber,V means for manually adjusting the tensionv of said spring equalizing discharge valve, an vequalizing discharge piston connected to saidlvalve, an exhaust valve, electrically operated means for holding the exhaust valve closed; means for opeiiing rsaid valve when the electrically operated means is rendered ineffective, and means operated by the opening of thesaid exhaust pvalve to connect thecontrol chamber to cham'- ber on one side yof, the equalizing discharge i iso the vbrake pipe pressure posing the control chamber pressure and opening the equalizing discharge valve to permit brake pipe pressure to exhaust to atmosphere until said brake pipe pressure has equalized with theV pressure in the control chamber.

19. A' brake pipe vent valve for automatic train stop apparatus comprising a brake pipe chamber, a control chamber, a main reservoir chamber, a movable abutment subject to the pressure in the brake pipe chamber, a movable abutment subject to the pressure. in the control chamber this latter abutment being larger in area than the train pipe pressure abutment, a movable abutment subject to the pressure in the main reservoir chamber, means rigidly connecting said abutments together, whereby the pressures in the control chamber and in the brake pipe chamber will oppose each other, a valve adapted to be opened and closed by the movements of the abutments and when open to admit air trom the main reservoir chamber into the control chamber, a valve adapted to be operated by the movements of the abutments and when open to 'exhaust air from the control chamber, aspring bearing on abutment and adapted to oppose the torce exerted by the pressure in the control chamber, means for manually adjusting the tension of said spring, equalizing ldischarge piston connected to said valve, an exhaust valve, electrically operated means for holding the exhaust valve closed, means for opening said valve when theelectrically operated means is rendered ineffective, and means-operated by the opening of the said exhaust valve to connect the control chamber to a chamber on one side of the equalizing discharge piston and to conneet the bralrepipe to a chamber on the .other side of the equalizing discharge piston, the brake pipe pressure opposing the control chamber pressure and openingthe equalizing discharge valve to permit brake pipe pressure to exhaust to atmosphere until said brake pipe pressure has equalized withv the pressureA in the control chamber.

20. A brake pipe vent valve for automatic train stop apparatus comprising a brake pipechamber, a control chamber, a movable abutment subject to the pressure in the brake pipe chamber, a movable abutment subject to the pressure in the Vcontrol chamber, this latter abutmentbeing larger in area than the train pipe pressure abutment, means rigidly connecting said two abutments whereby the pressures in said chambers will oppose each other, a valve adapted toybe Lopened and closed by the movements of the abutments and` when open to admit air into the control chamber, a valve adapted to be operated by the movements of theabutments and when open to exhaust air from the control chaman equalizing discharge valve, anv

ber, an equalizing discharge valve, an exhaust valve, means for controlling the oper- Y operated by the pressures in the said brake t,

pipe chamber in the control chamber for establishing a pressure in the control chamber at a 1aredetermined devree of Jressure below the pressure in the brake pipe cham-,

ber, an equalizing discharge valve, an equalizing discharge piston connected to said valve, an exhaust valve, electrically operated means for holding the exhaust valve closed, means for opening said valve when the electrically operated means is rendered ineffective, a slide valve chamber, a slide valve therein, a main piston connected thereto,

means for connecting the main reservoir tov the slide valve chamber, mea-ns permitting an equalization of pressures on opposite sides of the said main piston, a spring to hold the slid-e valve in inoperative position with -equalized pressure on opposite'sides of the main piston, a passage leading fronithe chamber at one side of the said piston to the Aexhaust valve said valve normally closing said passage, means whereby the'slide valve in operative position will connect the control chamber to a chamber on one side of the equalizing discharge piston and will connect the brake pipe toa chamber lonthe other side of the equalizing discharge piston, the brake pipe pressure opposing the control chamber pressure and opening` the equalizing discharge valve to permit the brake pipe pressure to exhaust to atmosphere untilsaid brake pipe pressure has equalized with theV pressure in the control chamber, and means whereby theslide valve in its inoperative position will connect the chambers on opposite sides ot the equalizing piston to atmosphere.

22. A brake pipe vent valve for automatic train stop apparatus comprising a brak-e pipe chamber and a control chamber, means for establishing a pressure in the control chamber at a predetermined degree of pressure below the pressure in the brake pipe chamber, an equalizing discharge valve, an exhaust valve, means for controlling the operation of the exhaust valve, and means automatically operating upon the opening of the said exhaust valve to open the equalizing discharge valve, the brake pipe pressure l opposing the control chamber pressure to hold the equalizing discharge valve open to permit brake pipe pressure to exhaust to atmosphere until said brake pipe pressure has equalized with the pressure in the control chamber, a main reservoir connection, a brake valve connection, a Valve controlling communication between said connections, and means operating to close said controlling valve when the exhaust valve is open.

23. A brake pipe vent valve for automatic train stop apparatus comprising a brake pipe chamber and a control chamber, means operated by the pressures in the said brake pipe chamber and in the cont-rolchamber for establishing a pressure in the control chamber at a predetermined degree of pressure below the pressure in the brake pipe chamber, an equalizing discharge valve, an equalizing discharge piston connected to said valve, an exhaust valve, electrically. operated means for holding the exhaust valve closed, means for opening said valve when the electrically operated means is rendered ineective, a slide valve chamber, a slide valve therein, a piston connected thereto, means for connecting the main reservoir to the slide valve chamber,

means permitting an equalization of pres' sures on opposite sides of the said piston, ay spring to hold the slide valve in inoperative position With equalized pressure on opposite sides of the piston, a passage leading from the chamber at one side of the piston to the exhaust Valve said valve normally closing saidpassage, means whereby the slid-e valve in operative position Will connect the control chamber to a chamberon one side of the equalizing discharge piston and Will connect the brake pipe to a chamber on the other side of the equalizing discharge piston, the brake pipe pressure opposing the control chamber pressure and opening the equalizing discharge valve to permit the brake'pipe pressure to exhaust to atmosphere until said brake pipe pressure has equalized With the pressure in the vcontrol chamber, a main reservoir connection, a brake valve connection,v

a Valve controlling'.communication between said connections, and means operating to close said controlling valve when the eX- haust valve is open.

In testimony 'whereof I hereunto aiiix my signature. Y l Y SPENCER G. NEAL. 

